Solid State vs Tube Amps

By Victor Oshiro | Posted May 8, 2013 at 10:03AM
Every so often I'd post one of my 'rants' here but I've tended to stay away from that format. Basically I give you my 2 cents worth but not in a review of a particular product. Lately all the mail I've been getting are "why don't you test this amp" or "you seem to have a bent against solid state amps". Nothing could be further from the truth. I view an amp as a tool - part of the total package that gives me a sound. I'm a tone chaser at heart - always looking for new, better, or just different tones. You'd be a little worried if you went to a mechanic and he only owned one screwdriver and one size of wrench. That's how I view music gear - it can take a lot of different tools to get a sound sometimes and other times its as simple as plugging directly into the right amp. Today I'm going to cover some basics on solid state vs. tube amps, or more accurately these days, digital vs. analog amps.

A little history

Lets go where it all started. Early in electric reproduction of music it was discovered that a motor could be built by putting windings of wire (usually copper) around a shaft and a magnet outside of that. Pass a current through those windings and you can develop an opposite electrical field to the magnet. Resistance is created and the shaft spins. You can attach a lot of things to this shaft - a flywheel on a car to start its engine - or a platter to make a record player. Here's where I'm going with this. The earliest sound reproduction equipment that relied on electricity were record players but they weren't a true complete electric device as they lacked a critical piece of hardware - an amplifier. These early devices used a needle which through a tube similar to a brass instrument transmitted the sound to a large horn. No actual speaker. No volume control. In a loud room you couldn't raise the volume. Getting why this wasn't optimal?

Next someone was working with light bulbs. The filament in a light bulb produces light but someone experimenting was able to add filaments to do other work. In this case it was diode tubes that were created and then triode tubes. This is important as the triode is still with us today in tube amps as well as high end audio gear. So basically what does a tube do? A tube 'amplifies' the signal going through it. In record players this meant a weak signal coming from the needle could be converted to an electrical signal and then amplified with the use of tubes. This is the golden era of radio and early records - it was the high end audio of its time. 

Someone realized that a microphone hooked up into a tube circuit could amplify that so it was a natural progression to project singers over large bands and then eventually to mic up the instruments themselves. Next in all this it took someone to figure out how to construct the basic instrument pickup. Not a true microphone but a device that can take sound waves (and the movement of a metal string above it) and convert it to an electric signal. As guitars at this time were still hollow bodied feedback became a huge issue with mic'd guitars. Guess what happened next? Solid body guitars came along. Nowadays you can pick a guitar that is solid body, semi-solid bodied, or hollow body. Add more options - different style microphones and magnetic pickups to convert your sound into something an amp can use. As transistors hit the market it seemed logical that would be the next step in audio reproduction.

Tubes can be temperamental little devices. Their performance degrades over time as their is a mechanical and chemical element to their operation. Add in that they can be delicate when used in a device that gets moved a lot. Transistor radios had just shown up - small, light, able to be dropped with no effect on the equipment. It seemed this solved all the problems a traveling musician had but these early solid state amps had problems.

A lot of musicians were looking forward to more durable, light to carry amps. From everything I've read a lot of guys tried solid state amps in the late 60's and 70's but the results were not good. Why? This is something even the engineers of the time had to learn. See, an electrical circuit can operate at an optimum way. Keep turning up your volume and you reach a point where you exceed this optimum performance. In a tube amp we get distortion from the preamp tubes and overtones and some distortion from the power tubes. This is a sound that is musical and pleasing to the ear. Push an early solid state amp to this level and what you get is less pleasing - harsh and less musical sounding. For a lot of people this is where the story ends but a lot has changed since those early solid state amps. Today engineers have had more time to experiment and have more tools at their disposal to help them achieve certain sounds. This is where today's modeling amp comes from - more on that later.

So what is solid state? You can take a basic tube design, remove the tubes, replace them with components like transistors and diodes and bam you now have a solid state amp. This is exactly what early engineers did in fact. A tube can produce various results depending on its input - solid state devices like transistors are either on or off. This on or off design is what produced that shrill distortion 

Some of my experiences

My first amp was a Crate combo - two channels, 12 inch speaker, spring reverb. Pretty good distorted sound but not so memorable clean. And by ok distorted sound I mean by 80's standards. Basically this amp had a distortion pedal circuit built into its channel 2. A friend of mine Dave had a great Fender combo - two 12 inch speakers, spring reverb and beautiful clean sound. This thing was amazing. I knew tube was definitely the way to go after listening to this thing.

I worked in a small guitar shop at this time which meant I had to do everything - setup guitars, sweep the floors, move stock around, and repair whatever came in the door. This was a steep learning curve but I wouldn't have traded it for the world. As I worked through more and more designs I found more similarities than differences with often solid state components substituted for tube parts. This was that infamous shrill sounding design.

Fast forward many years later and my older son wants to play guitar. I bought him a basic package with the guitar, a small amp, a tuner and cord. Why blow a lot of money if your not sure someone is going to keep playing. Thankfully hes kept it up and next I bought him a Line6 modeling amp. Not being familiar with this amp I was a little (ok a lot) skeptical. When I got to try it I was blown away by the fact that this thing had great clean tones and many different settings all the way from a little grit all the way to heavy metal. I was fully intrigued  After tracking down a schematic and reading everything I could find it comes down to integrated circuits - a solid state component that can have multiple outputs. No longer is the signal on or off but now things can be adjusted. IC's make all the difference - the sound produced is more organic and natural sounding. I can still pick out the lack of a lot of overtones but the sound made is very very good. 

Later I worked on a couple of hybrid amps. The first was a Marshall Valvestate - a solid state amp that uses a tube in the preamp. The sound is very Marshall on the OD channel. Later I worked on a Line6 Bogner hybrid. Take the solid state preamp section of the Line6 and put a real tube amp behind it. The solid state preamp section feeds into preamp tubes and power tubes. Awesome results but if I would change anything I'd put an option in to cut the output power. Then I could turn up the volume level to get those sweet overtones without being too loud. At 100 watts I couldn't reach overtones at a comfortable volume.

So what should you use?

I'm going to get back to that tool analogy - pick the right amp for the job.

Practicing in a small space like a bedroom? Try a small solid state amp. These are less expensive and if it can model lots of other amps it gives you some flexibility. The Line6 has tremolo, chorus, delay, and flanger effects built in.

Recording at home or in a small studio? I say go with a small tube amp like a Fender Champ. You can turn up the volume to get into those sweet overtones. This is good for clean and distorted sounds. Did you know Jimmy Page recorded with tiny tube amps? I have a Crate V33 modded with an SLO circuit and which I've reduced the power from 33 to 18 watts. It sounds awesome clean and distorted. 

A club/church/small auditorium. Here it gets a little tricky. You could go with a larger amp and rely on its projection. My preference is to mic an amp or use its line out and run it through the PA system. Your choice of tube or solid state is really your preference.

Large stadium/big club. Here's where big amps came into their own in the 60's. PA's weren't designed for these sound levels back then. Nowadays if you play that style with a big stack you could sound good but you'll be deaf before too long. I'd use a nice tube amp - 30 to 50 watts - mic'd into the PA. Great overtones and with good monitor speakers I won't struggle to hear myself. Let the PA system do what it was designed to do. If you play darker metal with drop tunings stick to solid state. Lower tones are less muddled and your riffs will be more crisp. 

As for my amps - a have a solid state modeler combo (Line6), a small tube amp head (V33), a solid state bass combo amp, and a 100 watt tube amp. I use two different cabinets - both 4x12. One is setup with some very efficient Jensen speakers. The other has house brand speakers that are almost perfect copies of Celestion G12's. This gives me all the versatility I could ask for but I'm still searching for that perfect tube combo. For quiet practicing I have a Line6 Pod that can clip to my guitar strap and I plug my earbuds into. It has all the same versatility as the standard Line6 preamp and I use it in an amp effects loop in a pinch when I'm without a pedal board. My son leans to the 100 watt tube amp but I think that's more his age speaking than his actual needs. I lean towards the small tube head but I don't hesitate to grab that modeling combo to go jam with friends. 

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